20253640 has 64 divisors (see below), whose sum is σ = 50181120. Its totient is φ = 7296000.

The previous prime is 20253589. The next prime is 20253661. The reversal of 20253640 is 4635202.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 83920 + ... + 84160.

It is an arithmetic number, because the mean of its divisors is an integer number (784080).

Almost surely, 2^20253640 is an apocalyptic number.

20253640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20253640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25090560).

20253640 is an abundant number, since it is smaller than the sum of its proper divisors (29927480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20253640 is a wasteful number, since it uses less digits than its factorization.

20253640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454 (or 450 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 20253640 is about 4500.4044262710. The cubic root of 20253640 is about 272.5844195981.

Adding to 20253640 its reverse (4635202), we get a palindrome (24888842).

It can be divided in two parts, 2025 and 3640, that added together give a palindrome (5665).

The spelling of 20253640 in words is "twenty million, two hundred fifty-three thousand, six hundred forty".